1. Field of the Invention
The present invention relates to a refrigerant condenser for a vehicle air conditioning apparatus, in which a condensing portion where refrigerant is condensed and a super-cooling portion where liquid refrigerant separated in a receiver is super-cooled are formed integrally.
2. Description of Related Art
JP-A-8-219588 discloses a refrigerant condenser including a super-cooling portion and a receiver integrally. Liquid refrigerant separated in the receiver is super-cooled in the super cooling portion, for improving a cooling performance. The receiver is integrated with the refrigerant condenser for downsizing a space where the refrigerant condenser and the receiver are installed.
The conventional refrigerant condenser has first and second header tanks extending in the upper and lower direction, and a core portion disposed therebetween, which includes plural tubes through which the refrigerant flows horizontally. A refrigerant inlet pipe joint is provided at the upper end side of the first header tank, and a refrigerant outlet pipe joint is provided at the lower end side of the first header tank.
The insides of both header tanks are separated into plural spaces in the upper and lower direction, thus the refrigerant winds and flows from the refrigerant inlet pipe joint, and in the header tanks and the core portion.
The receiver is integrated with the second header tank, and the inside thereof communicates with the second header tank through a first communication hole formed at the lower portion of the header tank. The liquid refrigerant condensed in the condensing portion flows into the receiver through the first communication hole, and is stored therein.
A second communication hole is formed below the first communication hole, and a separator is provided in the second header tank for partitioning the first communication hole from the second communication hole. Thereby, the liquid refrigerant in the receiver flows into the second header tank through the second communication hole, and flows through the super-cooling portion while being super-cooled. The super-cooled liquid refrigerant flows out of the refrigerant condenser through the first header tank and the refrigerant outlet pipe joint.
In the conventional refrigerant condenser, the liquid refrigerant flows out of the receiver at the position in the vicinity of the bottom of the receiver, for constantly supplying the liquid refrigerant into the super-cooling portion even when the liquid refrigerant amount in the receiver fluctuates in accordance with the change of a cooling load. That is, the super-cooling portion is located at the lowest portion of the core portion.
However, when the vehicle engine idles, for example, to wait for a traffic signal, the cooling air having passed through the refrigerant condenser and a vehicle radiator might be lead to the air upstream side of the condenser through the lower portion of the condenser by the operation of a cooling fan, because there is no air flow generated by vehicle running. This cooling air has high temperature because it has passed through the condenser and the vehicle radiator, and heats the lower portion of the condenser. Therefore, the cooling performance of the supercooling portion is lessened, and the amount of the super-cooling of the liquid refrigerant is reduced.